The design of some reusable lighters incorporates a case having a hinged top and a removable insert. The insert contains the functioning mechanism of the lighter. Some lighters have removable inside units for refilling the inside unit with liquid fuel, whereas some lighters have permanent inside units with refill ports on the bottom or side of the lighter for refilling the liquid fuel reservoir in the inside unit. For removable inside units, the optimal fit between the inside unit and the case is when the inside unit can easily be extracted and reinserted by hand, without the use of tools. The fit of the inside unit to the case should not allow the inside unit to move inside the case during normal operation of the lighter. One method for ensuring this fit is to manually spread the sides of the inside unit at the bottom. After spreading the sides of the inside unit, this fit-up operation requires insertion of the inside unit into the case to check for fit. If the fit is not correct, the spreading step is repeated, and the process starts again until the fit is correct.
There have been many designs directed to the fit between the inside unit and the case for lighters.
U.S. Pat. No. 1,006,557 discloses a leaf-type spring (reference "o" in FIG. 1) attached to the inner wall of the outer case for securing the inside unit in the case.
U.S. Pat. No. 2,541,111 also discloses a leaf spring attached to the inside wall of the outer case for positioning and retaining the inside unit.
U.S. Pat. No. 2,571,435 discloses an inner container that is held in position by screws and therefore is not manually removable. Referring to FIG. 1, four structural members hold the corners of the container 2, and a bottom plate 19 that is held in position by a screw 21, holds the container 2 in position.
U.S. Pat. No. 4,133,450 discloses a table lighter arrangement where a disposable lighter is held firmly in the base by upstanding flexible fingers with ribs disposed thereon. When the lighter is inserted the upstanding fingers function as springs to apply a force to the lighter to hold it in position.
U.S. Pat. No. 4,625,861 also discloses a case for a lighter. As shown in FIG. 4, the case is designed to be smaller than the lighter such that a tight fit is achieved.
U.S. Pat. No. 4,901,848 also discloses an outer case for a lighter. The case provides a snug fit as shown in FIG. 5 or a living hinge as shown in FIG. 6.
U.S. Pat. No. 5,740,905 discloses a set of notched flaps at the top of the outer shell that deflect inward when the lighter is inserted and maintain a force against the lighter body to hold it in position.
The above-described patents provide solutions for the fit between the inside unit and the case that are generally expensive, difficult to manufacture, and subject to failure when exposed to repeated removal of the inside unit from the case. What is needed is a relatively simple, durable device for establishing and maintaining the proper fit between the inside unit and the case for a liquid refillable lighter with a removable inside unit.